Patch to add guarding parentheses to some macros in linux/input.h

[Simon Budig <simon.budig@kernelconcepts.de>]

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Hi all.

This is a patch to add guarding parentheses around some macro argument
uses. This is good practice to avoid pitfalls like this:

ioctl (fd, EVIOCGABS (have_mt ? ABS_MT_POSITION_X : ABS_X), &abs);

Which currently totally does not do what is expected.

The attached patch adds parentheses to ensure correct operator precedence.

Please consider this for inclusion into the Linux Kernel.

Thanks,
        Simon
- -- 
       Simon Budig                        kernel concepts GbR
       simon.budig@kernelconcepts.de      Sieghuetter Hauptweg 48
       +49-271-771091-17                  D-57072 Siegen

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commit c88a91cb31a158a5e993484d91a0634a2aab1a43
Author: Simon Budig <simon@budig.de>
Date:   Wed Jun 1 23:04:42 2011 +0200

    input: add guarding parentheses to macros
    
    Put parentheses around macro argument uses. This avoids pitfalls
    for the programmer, where the argument expansion does not give the
    expected result.
    
    Signed-off-by: Simon Budig <simon.budig@kernelconcepts.de>

diff --git a/include/linux/input.h b/include/linux/input.h
index 9e5393d..31dd2b8 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -109,19 +109,19 @@ struct input_keymap_entry {
 #define EVIOCSKEYCODE		_IOW('E', 0x04, unsigned int[2])        /* set keycode */
 #define EVIOCSKEYCODE_V2	_IOW('E', 0x04, struct input_keymap_entry)
 
-#define EVIOCGNAME(len)		_IOC(_IOC_READ, 'E', 0x06, len)		/* get device name */
-#define EVIOCGPHYS(len)		_IOC(_IOC_READ, 'E', 0x07, len)		/* get physical location */
-#define EVIOCGUNIQ(len)		_IOC(_IOC_READ, 'E', 0x08, len)		/* get unique identifier */
-#define EVIOCGPROP(len)		_IOC(_IOC_READ, 'E', 0x09, len)		/* get device properties */
-
-#define EVIOCGKEY(len)		_IOC(_IOC_READ, 'E', 0x18, len)		/* get global key state */
-#define EVIOCGLED(len)		_IOC(_IOC_READ, 'E', 0x19, len)		/* get all LEDs */
-#define EVIOCGSND(len)		_IOC(_IOC_READ, 'E', 0x1a, len)		/* get all sounds status */
-#define EVIOCGSW(len)		_IOC(_IOC_READ, 'E', 0x1b, len)		/* get all switch states */
-
-#define EVIOCGBIT(ev,len)	_IOC(_IOC_READ, 'E', 0x20 + ev, len)	/* get event bits */
-#define EVIOCGABS(abs)		_IOR('E', 0x40 + abs, struct input_absinfo)	/* get abs value/limits */
-#define EVIOCSABS(abs)		_IOW('E', 0xc0 + abs, struct input_absinfo)	/* set abs value/limits */
+#define EVIOCGNAME(len)		_IOC(_IOC_READ, 'E', 0x06, (len))	/* get device name */
+#define EVIOCGPHYS(len)		_IOC(_IOC_READ, 'E', 0x07, (len))	/* get physical location */
+#define EVIOCGUNIQ(len)		_IOC(_IOC_READ, 'E', 0x08, (len))	/* get unique identifier */
+#define EVIOCGPROP(len)		_IOC(_IOC_READ, 'E', 0x09, (len))	/* get device properties */
+
+#define EVIOCGKEY(len)		_IOC(_IOC_READ, 'E', 0x18, (len))	/* get global key state */
+#define EVIOCGLED(len)		_IOC(_IOC_READ, 'E', 0x19, (len))	/* get all LEDs */
+#define EVIOCGSND(len)		_IOC(_IOC_READ, 'E', 0x1a, (len))	/* get all sounds status */
+#define EVIOCGSW(len)		_IOC(_IOC_READ, 'E', 0x1b, (len))	/* get all switch states */
+
+#define EVIOCGBIT(ev,len)	_IOC(_IOC_READ, 'E', 0x20 + (ev), (len))	/* get event bits */
+#define EVIOCGABS(abs)		_IOR('E', 0x40 + (abs), struct input_absinfo)	/* get abs value/limits */
+#define EVIOCSABS(abs)		_IOW('E', 0xc0 + (abs), struct input_absinfo)	/* set abs value/limits */
 
 #define EVIOCSFF		_IOC(_IOC_WRITE, 'E', 0x80, sizeof(struct ff_effect))	/* send a force effect to a force feedback device */
 #define EVIOCRMFF		_IOW('E', 0x81, int)			/* Erase a force effect */